This invention relates to a gas sensor arranged to sense a concentration of a specified gas component in a measurement gas to be examined.
Conventionally, there is known a gas sensor using a laminated sensor element, as a gas sensor arranged to sense a concentration of a specified gas component in an exhaust gas discharged from an internal combustion engine of vehicle and so on, for a combustion control of the internal combustion engine. The laminated sensor element includes, for example, an element body, and a heater arranged to activate the element body by the heating.
U.S. Patent Application Publication No. 2003-159928 A1 (corresponding to Japanese Patent Application Publication No. 2003-322632) discloses a gas sensor including an element body having a cell and a heater. The cell has a solid electrolyte layer mainly made of, for example, zirconia, a pair of electrode portions mainly made of platinum and formed on both main surfaces of the solid electrolyte layer, and a pair of lead portions mainly made of platinum and connected with the pair of the electrode portions, and each of the pair of lead portions extending along the solid electrolyte layer. The heater has a pair of base layers mainly made of, for example, alumina, a heating portion mainly made of platinum and sandwiched between the pair of the base layers, and a pair of heater lead portions mainly made of platinum and connected with both end portions of the heating portion, and each of the pair of heater lead portions extending along an insulating layer.